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what are the types of differential stress?
- tensional- crust stretching
- compressive- crust shortening
- confining- undeformed sedimentary layers
- shear- bending and breaking
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what is strain?
the change in shape or volume of a rock caused by stress
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strain takes place in 3 stages:
- elastic deformation
- ductile deformation
- fracture
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type of strain depends on:
- temp
- confining pressure
- rate of strain
- presence of water
- composition of rock
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strain in crust produces _____, _______ and ______
joints, faults and folds
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what are strikes and dip symbols used to indicate?
age, lithology and structure
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_________ and ________ are most common types of faults
dip slip, strike slip
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what are three types of dip slip faults?
- normal-tensional stress
- reverse-compressive stress
- thrust-low angle reverse fault
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on a strike slip fault the relative motion on the fault plane is ________
horizontal
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what are two strike slip faults?
- left-lateral
- right-lateral
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what are the major fault types?
- normal
- reverse
- thrust
- left lateral strike slip fault
- right lateral strike slip fault
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what type is faults is one of most dangerous?
strike slip
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rocks are results of ductile information which are cause by?
compressive stresses
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what is a syncline?
concave upper arch with younger rocks in center of fold
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what is anticline?
convex upward arch with older rocks at center of fold
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what is afaulted fold?
severe compression
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in domes and basins, where is yonger and older rock located|?
- dome-oldest rock middle, younger rock outside
- basin-young rock in middle and older rock outside
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what is isostasy?
- newly built montains weathered and eroded
- mass reduced float higher in mantle
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volcanic mountains are formed by ________ and not ________
- volcanic products
- deformation
-
cascade mountains
- pacific northwest
- several active volcanoes
- active during late tertiary and quaternary
- volcanic arc above subduction zone
- juan de fuca and gorda plates subducted by north american plate
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which structures are developed at basin and range province?
horst and graben
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basin and range province
- located idaho nevada and utah
- decompression and high heat above subducted rift zone
- normal faults cause thickeneing, uplift and tensional stress
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which belts are highest and most structurally complex mountain belts?
fold and thrust
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how are fold and thrust mountains formed?
- large compressive stresses in crust and convergent margins when continental crust collides
- rocks in collison zone folded, faulted and thrust faulted
- crustal thickening pushes upward
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